Establishing computed tomography reference levels for chest and whole abdomen procedures with contrast in East Avenue Medical Center

Abstract

Computed tomography (CT) is a major contributor to medical radiation exposure. In the Philippines, national CT diagnostic reference levels (DRLs) have not yet been formally established, which may contribute to variations in dose practice. This study evaluated the potential usefulness of acceptable quality dose (AQD) for contrast-enhanced chest-to-whole-abdomen and whole-abdomen CT examinations at East Avenue Medical Center. Adult examinations were grouped by body mass index (BMI). Console-displayed volume CT dose index (CTDI_vol) and dose-length product (DLP) values were verified using a Diagnomatic Pro-CT phantom with RaySafe X2 and Radcal 10X6-3CT pencil ionization chambers. Image quality was assessed using image quality scoring criteria on a five-point scale, and AQD values were summarized using dose metrics from diagnostically acceptable examinations. A total of 59 examinations were screened, and 38 were retained for AQD analysis. For chest-to-whole-abdomen examinations, 21 cases were retained, of which 20 had complete dose records; CTDI_vol medians increased from 34.06 to 46.38 mGy and DLP medians increased from 1884.13 to 2523.80 mGy cm across available BMI categories. For whole-abdomen contrast-enhanced examinations, including intravenous and triple contrast studies, 17 cases were included; CTDI_vol medians ranged from 54.12 to 119.07 mGy and DLP medians ranged from 1671.29 to 2485.75 mGy cm. The results support the potential usefulness of AQD for local CT dose optimization, but do not yet establish robust institutional reference levels because some BMI groups had small sample sizes.